Walk a binary tree

walk-binary-tree.py

#encoding: utf-8

class Node:
    left = None
    right = None
    parent = None
    key = None

    def __init__(self, key):
        self.key = key

    def walk(self, code='', f=None):
        self.code = code
        if f:
            f(self)
        if self.left:
            self.left.walk(code + '0', f)
        if self.right:
            self.right.walk(code + '1', f)


class Tree:
    root = None

    def walk(self, f=None):
        self.root.walk(f=f)


def main():
    def _f(node):
        print "%-04s '%s'" % (node.code, node.key)

    t = Tree()
    t.root = Node('juuri')
    t.root.left = Node('eka')
    t.root.left.right = Node('toka')
    t.root.left.left = Node('kolmas')
    t.root.right = Node(u'neljäs')
    t.root.right.left = Node('viides')    
    t.walk(f=_f)


if __name__ == '__main__':
    main()